During assembly of an elevator installation there is these days increasing use of the roof of the elevator car by engineers as a work platform. This is particularly so in the case of assembly of elevators without scaffolding. In that regard, the car during assembly of the installation is suspended at a chain hoist or comparable lifting device which is in turn attached to the shaft head. With the help of the chain hoist the car is moved by the elevator engineer in the shaft to the position desired by the engineer and the elevator engineer can subsequently carry out his or her work from the car roof during the installation.
If one or more elevator engineers are now present on the car it has to be ensured that the car does not move in undesired manner in the shaft. In particular, it has to be ensured that in the case of failure of the chain hoist the car does not crash down in the shaft. At the same time, however, it has to be possible for the engineer to move the car without problem to the place, which is desired by the engineer, for carrying out the necessary work.
In order to realize this it is, for example, proposed in EP 1 254 070 to mount movable hooks on the elevator car, which hooks can be brought by way of a cable by an engineer into a position in which they hook into brackets, which are used for fixing the guide rails, or detent there. The hooks are brought by the engineer into the detent position when the engineer works on the car roof. They can be released with the help of the cable so that they do not engage in the corresponding fastenings for the guide rails. The engineer can subsequently move the car. The disadvantage in that regard is that the fastening elements for the guide rails are, in certain circumstances, mounted relatively far apart in the shaft. Thus, the engineer can assume only certain positions in the shaft with the car, namely those in which the hooks are in the vicinity of the fastening elements. In other positions the car would, in the case of failure of the chain hoist, drop a relatively large distance before the hooks engage in the fastening elements, which could lead to risk to the engineer.